Environ Ecol Stat (2017) 24:595–598 https://doi.org/10.1007/s10651-017-0392-0 Reply to “Comment: estimating abundance—a non parametric mark recapture approach for open and closed systems” Zia Rehman 1 · Yuantao Xie 2 Received: 16 October 2017 / Revised: 8 November 2017 / Published online: 22 November 2017 © Springer Science+Business Media, LLC, part of Springer Nature 2017 Abstract We do not agree with comments made by Schofield regarding the paper “Estimating Abundance: A Non-Parametric Mark Recapture Approach for Open and Closed Systems”. We consider that Schofield statements are mischaracterizations of the Rehman paper that are an attempt to make the paper a special case of the Darroch model. While the Darroch model is indeed very valuable, we do not see the Rehman et al. model as a special case. The non-parametric and innovative approach of the Rehman et al. paper is a departure from current maximum likelihood models that are commonplace in ecology literature. This departure and novelty makes it harder for many to accept that and Rehman et al’s paper is well supported by both empirical and mathematical results. 1 Reply to Schofield comments How can the Rehman et al. model be a special case of Darroch under cluster sampling and yet be invalid in open systems? Throughout its development, Rehman et al. present an open system multiple capture (aka cluster sampling) model. Rehman et al. present Handling Editor: Bryan F. J. Manly. This reply refers to the comment available at https://doi.org/10.1007/s10651-017-0382-2. B Zia Rehman zreimann@hotmail.com Yuantao Xie xieyuantao@uibe.edu.cn 1 Maryville University, St. Louis, MO, USA 2 School of Insurance and Economics, University of International Business and Economics, Beijing, China 123